Mykayla takes about a gram of cannabis oil each day to help ward off pain, nausea, muscle spasms and seizures that can be common side effects both of her illness and of the traditional treatments such as chemotherapy.

Doctors disagree on whether the risks associated with marijuana use might, or might not, outweigh the benefits for children as young as Mykayla. The American Academy of Pediatrics opposes using marijuana as medicine. Some doctors also say the long-term effects of marijuana on children are, at best, unclear.